class Animal {
	constructor() {
		this._age = 100;
		this.tellAge = () => {
			console.log(this._age);
		}
	}
	type = '鸟类';
	get age() {
		return this._age;
	}
	set age(value) {
		this._age = value;
	}
	static skill() {
		return 'eat';
	}
	birth() {
		return 'born';
	}
}

let a = new Animal();
console.log(a.age);
a.age = 10;
a.tellAge();
console.log(Animal.skill());

class Dog extends Animal { type = '犬科' };
class Cat extends Animal {
	constructor() {
		super();
		console.log(super.birth());
	}
	static skill() {
		return super.skill() + ' fish';
	}
}
const c = new Cat();
console.log(Cat.skill());

let A = class {
	constructor(name, url) {
		this.name = name;
		this.url = url;
	}
}
console.log(A.name);
let B = class C {
	constructor(name, url) {
		this.name = name;
		this.url = url;
	}
}
console.log(B.name);
